/Engine/Source/Editor/MaterialEditor/Public/MaterialEditingLibrary.h
Gets all direct child mat instances
static void GetChildInstances ( [UMaterialInterface](API\Runtime\Engine\Materials\UMaterialInterface) * Parent, [TArray](API\Runtime\Core\Containers\TArray)< [FAssetData](API\Runtime\CoreUObject\AssetRegistry\FAssetData) > & ChildInstances )